A practice I noticed Amazon doing on few pages of the website is just using a dirty image to communicate something instead of doing proper HTML.
Since those are mostly internal pages for logged in users, I doubt they do this to avoid scraping or something. It looks to me they are just being frugal on resources and someone on the team would just open Microsoft paint and do something.
I like it. It is counterintuitive. And that’s why they are worth a trillion.